Dogs could soon be used to sniff out Parkinson’s disease years before symptoms start to show.

Scientists are trying to discover which odor molecules are linked to the disease so that dogs can be trained to spot the illness.

Researchers at Manchester University first began to believe Parkinson’s might have a discernible odor when a woman in Perth, Scotland, with a highly sensitive sense of smell claimed she detected a change in the odor of her husband six years before he was diagnosed with the condition.

Joy Milne claimed her husband’s smell changed subtly years before any difficulty with movement started to emerge.

When researchers conducted tests with Mrs Milne they found she was able to identify people living with Parkinson’s from people without the condition by smelling skin swabs taken from both groups.

In one case, Mrs Milne identified an individual who had Parkinson’s but at the time had not been diagnosed with the condition, because they had no symptoms.

In most cases severe damage to the brain has already occurred by the time the symptoms of Parkinson’s start to appear

Although human ‘super-sniffers’ are very rare, dogs have been trained in the past to detect cancer, and now Manchester University and the research charity Medical Detection Dogs has joined together in a study that will use dogs to test skin swabs for Parkinson’s using their extraordinary sense of smell.

It is estimated that the percentage of a dog’s brain devoted to analyzing odors is 40 times larger than that of a human

“The full potential of dogs to detect human disease is just beginning to be understood,” said Claire Guest, Chief executive of Medical Detection Dogs.

“If all diseases have an odor, which we have reason to believe they do, we can use dogs to identify them.

“Dogs have 300 million smell receptors in their noses compared to our mere five million. They are first-rate bio-sensors and their ability to help us make important scientific advances should not be dismissed on account of their waggy tails and fluffy coats.

“Parkinson’s is a pernicious condition and to be able to extend the quality of life for those affected would be a highly significant step forward.”

Dogs sense of smell is around 40 times better than humans.

Parkinson’s affects one in every 500 people in the UK, around 127,000 in total and is caused by the deterioration of neurons in a certain part of the brain. People with the condition are left struggling to move and even speak.

But there is currently no definitive test and symptoms typically only start to show once more than half of the relevant nerve cells in the brain have already been lost.

Not only is the delay in diagnosis upsetting for people, it also prevents them starting treatment to help with their Parkinson’s symptoms.

The researchers are hoping to use the dogs to hone in on the chemical indicator of Parkinson’s found on the skin of people living with the condition.

Two Labradors and a cocker spaniel will next week start work on swabs from 700 people to spot a smell that appears years before victims start suffering from tremors and mobility problems.

The team will also be using mass spectrometers to split up samples into its component molecules, and they will also run each past the dogs to identify which key chemical indicator is involved in Parkinson’s.

Dr Beckie Port, Research Communications Manager at Parkinson’s UK, which is funding the study, said: “Detecting Parkinson’s is incredibly difficult as there is currently no definitive diagnostic test.

“Finding a chemical odor associated with Parkinson’s could have a huge impact. It promises to improve diagnosis and assist in the development of treatments that slow, or even stop, Parkinson’s.

“Research that aims to find this odor is still in the early stages. But dogs, with their keen sense of smell, may play a vital role in this discovery and bring about a significant advance in Parkinson’s research.”